(1) Field of the Invention
This invention relates to plugs for sealing the flow of metal from molten metal receptacles such as steel making furnaces, ladles, and the like.
(2) Description of the Prior Art
Prior art devices of this type have relied on a number of different plugs or stoppers. See for example U.S. Pat. Nos. 3,540,627, 4,010,936 and 4,030,709.
In U.S. Pat. No. 3,540,627, a conical metal plug is attached to the end of a supporting rod and has a conical pad positioned thereover, the conical pad being formed of a layer of refractory fibers, such as alumina silica fibers, and a layer of glass fibers, the metal plug and its conical pad being insertable in the passageway defined by a tap hole in a molten metal receptacle.
U.S. Pat. No. 4,010,936 discloses a stopper plug in a shape corresponding exactly to the shape of the tap hole and formed on non-porous refractory material, organic fibrous substance, and inorganic fibrous substance together with a combustible substance, the material forming a porous molding which is elastic and capable of shrinking and deformation so that it will remain in the tap hole of the vessel under nominal pressure of the molten metal and will deform and be extruded from the tap hole by the increasing pressure of the molten metal when the vessel is tilted.
U.S. Pat. No. 4,030,709 discloses the use of a ceramic plug in the shape of a hollow cone over a solid backing plug which is maintained in place until the molten metal solidifies against the plug to seal off the tap hole.
The present invention discloses a novel, expandable, hollow cone-shaped stopper plug and a wedge-shaped member movable therein to expand the same in the tap hole of a molten metal receptacle so as to effectively seal the tap hole for a predetermined time.